Joe Spencer prefers brains over brawn on his offensive line of the Chicago Fire.

“There’s no place for dump people on the line,” says the assistant coach. “I’ve seen guys who could block a house away, but they only had muscle between their ears.”

“When you see as many different defensive fronts as we’ve seen already in the World Football League, and 95 per cent of our blocking is called at the line, you damn well better know what you’re doing,” he noted after yesterday’s practice at Maryville Academy in Des Plaines.

Spencer is proud of his interior linemen, namely Guards Mike Sikich and Dave Bradley, Tackles Steve Wright and Glenn Hyde, and Center Guy Murdock, but mostly because of their intelligence.

It was their adjustment to Philadelphia’s defense that led to the Fire’s 32-29 victory last Wednesday and the impressive rushing of Cyril Pinder [151 yards] and Mark Kellar [112]. Spencer expects to see a similar set from Detroit Thursday night in their nationally-televised game at Ypsilanti, Mich.

"Philadelphia doubled on our wide receivers, that's four people on two, and that opened it up for our running," said Spencer, who coached the offensive line for the New York Jets Super Bowl Champions. Virgil Carter audibled about a third of the time and took advantage of their set. If you're running well, and the defense doesn't change in response, why should you change?"

Spencer is a bear of a man, former star lineman wiht Green Bay, Cleveland, and Philadelphia, but he treats he players with a mature hand. "What sense is there in yelling at a player in practice and embarrassing him in front of the group?" said Spencer.

"That just makes him feel uptight, and that's when a player really starts making mistakes. I try to talk to him man to man, tell him what he did wrong, and advise him how to correct it. That works best for me."

Spencer also realizes that fans won't notice a good block unless, he says, "it's blood-curdling," but insists anything that makes a defender move a half-step out of position and miss a tackle, is an effective block in his book.

"We had 47 running plays against Philadelphia, and not one missed assignment," he said. "When you see Virg scrambling that's not because our line broke down, that is a set type of blocking and Virg throws as well on the run as any quarterback I've senn."

Spencer added: "What makes you proud is that you never see our players walk to the line of scrimmage. When it comes from within, when you don't have to push, that's nothing but the players' pride. And that cures whatever mistakes you have.

FIRESIDE CHAT - Safety Barry Ruffner, who fumbled a punt that led to a Bell touchdown, has quit the Fire what Coach Jim Spavital calld "personal reasons." ... The visitors' locker room in Ypsilanti is being remodeled and the Fire may have to dress at their motel instead. "Welcome to the World Football League," sniped a Fire aide.